RFR: 8337712: Wrong javadoc in java.util.Date#toString(): "61" and right parenthesis

[Per Minborg]

This trivial PR proposes to add a missing parenthesis in `java.util.Date::toString`.

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Commit messages:
 - Update copyright year
 - Add missing parenthesis in Date::toString

Changes: https://git.openjdk.org/jdk/pull/20439/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20439&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337712
  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20439.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20439/head:pull/20439

PR: https://git.openjdk.org/jdk/pull/20439